The spine is a column of vertebrae divided into three sections (cervical, thoracic and lumbar). The vertebrae are separated by small cartilaginous cushions identified as intervertebral discs which contain a jelly-like substance called the nucleus pulposus. Additionally, each vertebrae contains several bony projections known as processes which attach to adjacent muscles. These processes interlock at areas termed facet joints and, in concert with the surrounding attached muscles, allow the spine to twist or bend.
When abnormalities such as disc herniation, spinal stenosis, spinal degeneration, cauda equina syndrome, or the like occur in an individual, nerves within or adjacent to the spinal column may become inflamed or impinged resulting in the individual experiencing various forms of pain, loss of flexibility, loss of motion, and possibly loss of bladder and/or bowel control. Additionally, these abnormalities may result in the development of spondylolisthesis, a condition in which one vertebrae slips forward over another.
Although conservative treatments are most often recommended, certain types of injuries, or conditions which result in intractable pain and the possibility of permanent loss of mobility often must be treated surgically.
Typical surgical procedures such as discectomy, laminectomy, and spinal fusion require the surgeon to first gain access to the interior of the spinal column and to the interior faces of the bony processes using either an anterior or posterior approach.